The invention concerns an optical semiconductor transceiver and more particularly a light emitter and receiver integrated on the same substrate and connected to the same optical waveguide.
To be more precise, the invention concerns an opto-electronic device monolithically integrating a Perot-Fabry semiconductor laser or a distributed network reflector (distributed feedback DFB) and a photodetector, each operating at a particular wavelength and both positioned in-line on the same waveguide. Emission and detection can be performed simultaneously with the possibility of having the detector operating alternately with the laser emission.
Owing to the advantages of optical transmission, (capacity, space requirement, immunity to interference, etc.), subscriber connection to networks, such as video broadcasting networks or integrated services digital networks (ISDN), by means of fiber optics is becoming increasingly attractive. Moreover, bi-directional transmission on the same fiber should make it possible to reduce line costs.
However, this requires terminal equipment such as transceivers of low cost, which calls for new structures monolithically integrating the two functions of emission and reception with simultaneous input and output on the same fiber.
Different technical solutions are known, implemented either by monolithic integration or by hybridization of the two functions of emission and reception.
Thus, the B. HILLERICH et al document "Transceiver module for single mode fiber subscriber link", IOOC'89, Kobe, vol. 2, page 76-77 describes a dual wavelength duplexer for bi-directional links made using hybrid technology.
The K. YAMAGUHI et al document EOOC' 87, pages 275-278 describes a duplexer connecting a luminescent diode and a photodetector using hybrid technology.
The V. KOREN et al document, IOOC'89, KOBE, vol. 2, page 8-9 describes a three DFB laser configuration with separately adjustable wavelengths connected by means of a mixer in an optical output amplifier, the whole assembly being monolithically integrated.
Bi-directional optical links and in particular transceiver light emitting diode type components are described in French patents numbers 2 273371, 2 406896, 2 426295, 2 493047. However, these types of components perform the emission and detection functions alternately and not simultaneously.
As regards the monolithic integration of several functions, different devices have been manufactured.
For example, the integration of a distributed feedback (DFB) laser and a low loss waveguide is described in French patent No. 2 596 529 and in the JC. RENAUD, R. RONDI, Y. BOURBIN, A. TALNEAU, G. GLASTRE, G. VILAIN, A. ENARD, R. BLONDEAU document, "Monolithic integration of a 1.55 .mu.m DFB laser and a waveguide by MOCDV epitaxies" 3rd Microelectronic and Opto-electronic National Days III-V, March 1990, in addition to the integration of a demultiplexer and its access waveguides described in Interim Report ESPRIT 263, Period 09, Section A "Monolithic integration of a multi/demultiplexer and its access waveguides" or the integration of an optical amplifier and its passive guides described in French patent application No. 89 17087.
Finally, the T. L. KOCH et al document, "Simple In-Line Bi-Directional 1.5 .mu.m/1.3 .mu.m Transceivers"--12th IEEE International Semiconductor laser conference, Sep. 9-14, 1990 DAVOS Switzerland, describes a semiconductor laser and detector aligned and produced on the same substrate.